After 6 years the penthouse coating (Raptor) became dull and chalky. I considered recoating but that's a lot of work and would require removing the rack.http://www.sportsmobileforum.com/for...iner-6660.html
Brushing a clear coat seemed like the easiest solution. Clear Shot by Rust Bullet. "Clear Shot is a revolutionary single component UV resistant clear coat urethane that won't crack, chip, yellow, or peel and dries to an incredibly hard water clear finish. Clear Shot can be applied over painted or unpainted surfaces including wood. It can be brushed, rolled, or sprayed, is self-leveling and will not leave brush marks".
After thoroughly washing the top with soap and water I wiped it down with denatured alcohol. I used a brush, it applies very easily. Avoid drips and don't apply the second coat until the first coat has dried or it could develop tiny air bubbles. The first coat completely soaked in. The second coat dried with a thick wet gel look. I am very happy with the result and if it holds up this will be a great $50 solution. One quart covered the entire top with two coats.
Right side does not have Clear Shot, left side has one coat.
Think I'm the first person to apply this stuff so you might want to wait for 6 months or so before following my lead. I will update if it does not hold up.